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UNIVKRSILYOl    ILLINOIS  BULLETIN 

ISSUED     WEEKLY 

Vol.    XI.  JULY   13,    L914.  v.    46 

[Entered    as   second-class    matter    December    LI,    1912,    at    the   i»>st   office   at 
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BULLETIN   No.  22 
DEPARTMENT  OF  CERAMICS 

R.    I'    Sill. I..     Acting  Director 


THE  INFLUENCE  OF  CHLORIDES  OF  CAL- 
CIUM AND  IRON  WHEN  PRECIPITATED 
IN  A  PORCELAIN  BODY 


SOME   COBALT-URANIUM   COLORS 

BY 
B.   S.   RADCLIFFE 


mm.isHKD  by  the  university  of  Illinois,  urban  \ 


1  9  1  3  -  I  ')  I  4 


Authorized   Rt>prinl    from    I'olumi    XVI,    1914,   Transactions  American  <• 


THE  INFLUENCES  OF  CALCIUM  AND  IKON  CHLOR- 
IDES PRECIPITATED   IN  A   PORCELAIN   BODY 

BY    B.    S.    i:  \Ih  i  n  '  i 

The  production  of  vitrified  red  Horn  tile  has  given  manu- 
facturers considerable  trouble.  Pra  rieally,  the  only  solution  of 
the  problem  has  been  to  secure  a  good  red  burning  clay,  and 
burn  to  a  degree  of  vitvfic  tion  such  thai  the  red  color  is  no1  de 

stroyed.    In  mos1  instan<    >.  ii  lias  been  found  impossible  t ake 

red  bodies  thai  have  I  -s  Hum  four  or  five  percenl  absorption, 
and  in  many  cases  !he  absorption  is  considerablj  greater  than 
this. 

Good  red  bodii  -  can  be  made  by  mixing  the  proper  ; >unts 

of  feldspar  and  Mini  with  "Helmstadter"  clay,  and  burning  to 
practically  complete  vitrification. 

This  clay  is  very  line  grained,  plastic,  and  is  red  in  color, 
The  original  red  color  of  the  clay  is  only  slightly  altered  during 
burning,  up  to  tin-  point  when  the  porosity  is  reduced  to  aboul 
three  percent.  A  higher  temperature  causes  the  red  color  to 
deepen  and  gradually  cihange  to  dark  brown  and  finally  black. 
The  deepening  of  the  color  begins  aboul  cone  '>.  and  by  cone  8 
tin-  body  is  dark  brown  to  black.  The  burning  qualities  of  this 
clay  seem  to  be  duo  to  the  fad  Unit  the  iron  is  present  in  a 
highly  disseminated  state. 

This  investigation  was  made  \<>  determine  whether  uniform 
colors  of  iron  in  varying  shades  could  lie  produced  by  precipi- 
tating the  chlorides  of  iron  and  calcium  in  a  body. 

A  cone  10  porcelain  was  chosen  for  the  body.  It  is  not 
considered  an  ideal  one  for  the  production  of  red  tile,  and  one 
containing  more  ball  clay  in  place  of  the  china  clay  would  prob- 
ably he  better,  since  it  would  have  less  porosit.\  in  bhe  >\ry  state 
and  would  require  less  fluxing  action  \'<>v  complete  vitrification 
on  that  account. 

Procedure.      The   three   corner  bodies  as   gfoowi the   i  ri 

axial  diagram  were  mixed  by  wel  grinding  for  five  hours  in  a 
poreelaindined  hall-mill.  The  tri-axial  group  of  66  bodies  was 
made  by  blending  bhese  I  hree  bodies. 


CALCIUM    AND   1RO.V    CHLORIDES    IN    PORCELAIN    BODY 


E^CQ^ 


CALCIUM    AND    [RON    CHLORIDES    IN    PORCELAIN    BODJ  .<, 

The  mixtures  were  pu1  in  frail  jars  and  shaken  thoroughly 
so  as  to  obtain  uniform  mixtures.  The  chlorides  were  precipi- 
tated by  adding  XII, oil  and  ■Ml,  B003  and  shaking.  The 
slips  were  allowed  to  stand  for  a  day,  after  which  Bhey  were 
poured  into  plaster  molds.  When  the  excess  water  had  been  ab- 
sorbed the  bodies  were  removed  from  the  molds,  and  dried  in  an 
oven  to  200  0.  After  crushing  in  a  porcelain  mortar,  triangular 
floor-tile  were  made  by  the  dry-press  process,  aboul  1<»  percent  of 
water  being  used.  Thej  were  burned  to  cones  5,  7.  9  and  11  in 
an  open,  down-draft,  gas-fired  tesl  kiln. 

Results.  Those  bodies  bigh  in  iron  were  most  plastic,  and 
those  high  in  lime  were  Least  plastic.  This  was  shown  both  by 
the  working  properties  of  the  bodies  in  the  plastic  state  and  l>\ 

the  strength  of  the  dried  tile. 

Vitrification— None  of  the  bodies  were  completely  vitrified 
at  cone  5,  although  those  high  in  iron  and  lime  were  hard  and 
dense,  thu.se  liig-h  iu  lime  being  the  hardest.  At  cone  7.  all  bodies 
containing  over  four  percenl  of  iiuxes  were  vitrified.  All  bodies 
were  completely  vitrified  at  cone  9,  those  containing  over  7  per- 
cent of  fluxes  being  overburned. 

Bodies  containing  -\  percent  and  over  of  fluxes  were  over- 
burned  at  cone  11.  The  remainder  retained  their  shape  but  had 
a   glassy  surface  with  the  exception  of  1,  2  and  3. 

Color— Bodies  free  from  iron  burned  white  and  were  prac- 
tically uniform  in  color  at  vitrification. 

Tlio.se  containing  1  percent  of  iron  were  cream  colored  when 
burned  under  oxidizing  conditions,  but  a  good  uniform  graj 
color  was  obtained  w men  the  tile  were  reduced  ai  the  end  of  the 
burn.  The  lime  had  very  Little  effect  upon  the  color  of  bodies 
containing  1  percent  of  iron.  Bodies  containing  l!  percent  of 
iron  were  pink  or  Light  red  at  cone  5,  above  which  temperature 
they  changed  to  brownish  buff  with  the  exception  of  No.  4.  which 
became  dark  yellowish  gray. 

Bodies  containing  4  bo  1<>  percent  of  iron  burned  red  to  dark 
Vi'il  at  cone  .">.  Those  containing  f.  5  and  6  percent  were  still  wA 
at   cone  7.      The  color  was  much   deeper  than   at    cine  .">  and   in- 


4  CALCIUM    A.ND    IRON    CHLORIDES   IN    PORCELAIN    BODY 

ereased  with  increased  iron.     Two  percent  of  lime  did  not  affect 
the  color  of  bodies  containing  5  percent  or  over  of  iron. 

The  remainder  of  the  series  did  net  produce  desirable  colors 
for  floor  tile. 

CONCLUSIONS 

Uniform  gray  colors  of  pleasing  shades  can  he  made  by  pre- 
cipitating 0  to  2  percent  of  iron  in  a  porcelain  body  and  burning 
properly. 

Uniform  red  colors  can  be  produced  by  precipitating  4  to  G 
percent  of  iron  in  a  porcelain  body  which,  if  burned  properly, 
would  not  have  more  than  3  to  4  percent   porosity. 

( leramic   Laboratory, 

r/niversitj    of    Illinois 

DISCUSSION 

Mi-.  Parmelee:     I   should   like  to  ask  the  reason   for  using 

calcium   salt. 

Mr.  Uadclijfe:  Calcium  chloride  was  added,  because  it  is 
;i  soluble  salt  :  and  it  was  thought,  that  the  intimate  mixture  of 
the  calcium  and  iron  obtained  in  this  way,  might  throw  some 
light  on  the  cause  of  the  varied  color  effect,  produced  by  iron  in 
different  clays. 


SOME   COBALT-URANIUM   COLORS 


B1    B.   S.    BADCLIPFB 

There  are  four  coloring  oxides,  namely,  copper,  chromium, 
nickel  and  iron,  which  under  proper  conditions  produce  green 
colors  in  bodies  and  glazes.  In  physical  mixtures,  \\e  are  able  to 
produce  greens  by  blending  blue  and  yellow. 

The  object  of  this  investigation  was  bo  determine  whether 
green  could  be  produced  by  blending  cobalt-blue  and  uranium- 
yellow. 

Series  A   was  made  up  as   follows: 

TABLE    I— SERIES    A 


A. 

v. 

A3 

\  t 

AD 

\a  L'.O:  6H.0 

\li(  )H) 

1  .0 
50.0 
40.0 
25.0 

0.9 
50.0 

40.0 
25.0 

0.8 
50.0 
4O.0 
25.0 

0.7 
50.0 
40.0 
25.0 

0.6 
50. 0 
10. 0 

Zn( )               

25.0 

The  stains  were  thoroughly  mixed,  calcined  to  cone  5,  ground 
to  pass  a  200  mesh  screen  and  added  to  a  mat  glaze  having  the 
formula, 

0.1  K,o     j 

0.2  OaO    I   0.36  Al,<>:;     1.36  Si<>. 

0.7  PbO    J 
The  glaze  was  then  burned  to  cone  05.     The  result  was  a  yellow- 
ish green  glaze  with  blue  specks.     This  was  due  bo  the  fact  thai 
the  cobalt  was  not  thoroughly  disseminated. 
A   blue  stain 

CoA  i<» 

Calc.   A1208    4o 

ZnO   45 

was  then  made,  calcined  to  cone  7.  and  ground  to  pass  a  200 

mesh  screen. 

Three  frits  wen-  made  using  the  mat  glare  as  before. 


SOME  COBALT-rRANH'M    COLORS 
TABLE    II— SERIES     B 


Feldspar 

CaCO» 

Red  lead    

Eng.  china  clay 
Tenn.  ball   clay. 

Flint 

Blue    stain 

Na2U20,  6  H20 . 


17.6 

l ; .  6 

17.6 

6.3 

6.3 

6.3 

50.5 

50 .  ."> 

50 . 5 

11.0 

11.0 

11.0 

10.0 

10.0 

10.0 

4.6 

4.6 

4.6 

10.0 

10.0 

10.0 

25.0 

35.0 

45.0 

When  applied  as  glazes,  B  1  gave  an  olive  green,  B  2  and 
B  3  rich  chocolate  browns.  These  results  indicate  thai  the  ratio 
of  uranium  to  cobalt  is  too  high. 

The  nexl  step  tried  was  to  use  the  nitrates  of  coball  and 
uranium,  l)\'  fritting  in  Hit-  mat  glaze. 


TABLE     III  — SERIES    C 


ci 

c., 

':: 

Feldspar 

i ; .  6 

6.3 

50.5 
1  1  .0 

10.0 
1.6 

3.5 

10.0 

17.6 

6.3 

50.5 

1  1  .0 

10.0 

1  .6 

3.5 

L2.0 

L7 . 6 

CaCO; 

c>.:; 

Red    lead    

50.5 
11.0 

Tenn.  ball   clay 

Flint 

10.0 

4.6 
3.5 

1  'milium    nitrate 

1  5 . 0 

The  frits  were  ground,  and  a  .scries  of  glazes  made  by  blend- 
ing with  the  original  mat   glaze. 

Bright  glazes  vcie  made  by  adding  20  parts  of  flint  to  the 
frits  of  this  series. 

The  mat  glazes  were  olive  green,  (',   having  a   bluish  shade. 

Of  the  bright  glazes  C3  was  deep  green  in  color,  and  Cj  and 
C,  were  green  with  a  bluish  shade. 


SOME  COBALT-1  RANI1   M    COLORS 

Conclusions:  Green  glazes  and  mats  can  be  made  by  blend 
ing  cobalt  and  uranium  in  the  righil  proportions,  which  is  be 
tween  four  and  five  parts  of  uranium  nitrate  to  one  pari  of  co 
bait  nitrate. 

( leramic   Laboratory  • 

I  niversitj    >■!    Illinois. 

DISCUSSION 

Prof.  Orion:  I  do  not  know,  whether  there  has  ever  been 
any  repor1  made,  about  the  peculiar  green  developed  by  one  of 
the  roofing-tile  plants  in  this  country  l>y  the  use  of  coball  oxide 
and  sulphate  of  antimony.  These  coarsely  ground  chemicals 
were  added  to  a  roughly  prepared  glaze;  and  the  resiiH  was  thai 
they  succeeded  in  getting  a  very  passable  green.  At  least  it 
liooked  like  a  good  green  om  the  roof,  hut  if  looked  a1  close  by, 
the  size  of  the  blue  and  yellow  spots  was  so  large  as  to  be  offen- 
sive. The  reason,  thai  they  did  this,  was  thai  they  were  working 
in  ;i  sulphurous  close  atmosphere,  that  spoiled  other  greens,  and 
they  thought,  that  if  they  had  a  sulphate  bo  start  with,  it  would 
not  do  any  harm. 

Mr.  Radcliffe:  I  might  say  that  a  man  in  the  berra-cotta 
business  in  Kansas  bold  me  that  he  used  cobalt  and  uranium  to 
produce  greens.  lie  did  not  led  me,  however,  until  we  worked 
:t  out.  lie  was  using  il  for  polychrome  work.  The  cobalt-uran- 
ium green  that  ho  produced  was  better  than  any  other  green  that 
he  could  make  for  this  purpose.  It  did  no!  run  or  blend  oil'  with 
the  white,  but  instead  he  could  get  a  firm  line  between  the  green 
and  the  white,  or  whatever  base  was  beneath  the  green  poly- 
chrome work. 


MHBBBMtf^HU 


UNIVERSITY  OF  ILLINOIS-URBANA 


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